This invention relates generally to methods and apparatus for printing on a media sheet using inkjet printing techniques, and more particularly, to a system in which media sheet drying time is estimated and adjusted.
Inkjet printing techniques involve the ejection of drops of liquid ink onto a media sheet to form symbols, characters or graphics. Upon completion of printing, the ink on the media sheet typically is wet. Before the media sheet can be handled, folded or re-fed into a paper path, and before a media sheet can be laid over the wet media sheet, the media sheet must be dry enough to avoid ink smearing.
As faster printing speeds and duplex printing become more desired, the wet media problem becomes more significant and costly. One approach has been to utilize a dye that penetrates the paper fibers and is less susceptible to smearing. Shortcomings of this approach include, feathering along region edges, decreasing in the optical density due to paper fibers reflecting more incident light.
Another approach to achieve higher printing speeds has been to include a one-sheet buffer area. The buffer is formed by output rails. When a media sheet is printed, it is moved along output rails where it is suspended above an output tray. By doing so, the top sheet in the underlying output stack is given additional time to dry. When the next sheet is printed, the prior sheet is dropped onto the output stack giving it additional time to dry. However, as the desire for still faster printing speeds continues, and as the desire for duplex printing manifests, additional techniques are needed.